基于转炉热平衡的石灰石CaO理论替代比研究

Study on theoretical substitution ratio of lime stone with CaO based on thermal equilibrium in BOF steelmaking process

通过转炉热平衡计算,建立了转炉富余热量与铁水成分和温度、废钢加入量和转炉出钢温度等工艺参数之间关系式;定义了转炉用石灰石代替活性石灰炼钢的CaO理论替代比η,并建立了石灰石CaO理论替代比与转炉富余热量之间的函数关系。研究表明:1)提高入炉铁水温度和铁水含碳量可显著提高转炉石灰石CaO理论替代比;2)铁水中的硅含量对石灰石CaO理论替代比的影响与铁水入炉温度有关,当入炉铁水温度低于1 300℃时,提高铁水硅含量能使石灰石CaO理论替代比增加;当入炉铁水温度高于1 300℃时,石灰石CaO理论替代比随铁水硅含量的增加反而下降;3)在转炉终渣碱度和出钢温度一定时,减少废钢加入量可以大幅度提高转炉用石灰石代替活性石灰炼钢的CaO理论替代比。

Based on the heat balance calculation of converter,relationship between surplus heat and related parameters including the compositions and temperature of hot metal,amount of scrap addition and converter tapping temperature has been established. Theoretical substitution ratio η of limestone with active lime in converter steelmaking is defined,and the function relation between the substitution ratio η and the surplus heat of converter is established. The results indicated：（ 1） The CaO theory substitution ratio of converter could be significantly improved by increasing the temperature and carbon content of iron liquid.（ 2） When the hot metal temperature was lower than 1 300 ℃,theoretical substitution ratio of CaO could be increased with increasing the silicon content of hot metal; while the hot metal temperature was higher than 1 300 ℃,theoretical substitution ratio of CaO decreased with increasing the silicon content of hot metal.（ 3） With the conditions of constant slag basicity and tapping temperature,theoretical substitution ratio of CaO could be significantly increased by reducing the amount of scrap steel.